setup: Add argparse, remove pexpect as dependencies
setup: Add argparse, remove pexpect as dependencies

Argparse is not included with python 2.6, but we can install it
easily enough.

Pexpect is not a direct dependency of cxmanage. It belongs in the
pyipmi setup script instead.

Cynerva/cxmanage,SilverLiningSystems/cxmanage-test2,SLS-Dev/cxmanage,SLS-Dev/cxmanage,SilverLiningSystems/cxmanage-test2,Cynerva/cxmanage,SilverLiningSystems/cxmanage-test,SilverLiningSystems/cxmanage-test